Playing through 0.6.0b (I think..)

If after gaining enough experience to acquire a class, but can also upgrade one of my Stats Factors (Physics, Magic etc)

I can select a class so it's there for confirmation I want that class, upgrade my stats factor, then also select the class that was there.

This ends up giving negative XP

Example.

Daisy - 100XP free. Select Acolyte. Don't click unlock, instead click Upgrade. Upgrade Physics Factor by 1 (100XP). Close the factor upgrade, unlock Acolyte. Now at -100XP